The present invention relates generally to hand-held information processing devices and, in particular, to a portable hand-held information processing device keyboard which can automatically switch from data synchronization to keyboard function.
In the fast paced business community, a personal digital assistant (PDA) or other hand-held device, which combines computer, communication and consumer electronics technologies, is becoming very popular due to its advantageous features including writing notes, recording names, addresses and phone numbers, and developing an appointment calendar. In the example of FIG. 1A, a hand-held information processing device 100, such as PDA, is typically mounted on a cradle 110 connected to a desktop or notebook computer 150 through a cable 120. In this manner, the hand-held information processing device 100 can synchronize and backup data with the computer 150. On the other hand, for the purposes of efficient and accurate data input and ease of text information handling, a conventional portable keyboard 130 is attached to the hand-held information processing device 100 to key in data as shown in FIG. 1B.
A hand-held information processing device attracts users due to its pocket size which allows easy transport. However, users still have to carry a cradle and a portable keyboard to synchronize data and perform data input in some occasions. It is inconvenience for hand-held information processing device to carry the additional devices.
Accordingly, it is necessary to develop a portable keyboard for a hand-held information processing device, unencumbered by the limitations associated with the prior art.
It is an object of the present invention to provide an input apparatus for a hand-held information processing device, particularly, an input apparatus providing both hand-held input and data synchronization functions.
It is another object of the present invention to provide a portable keyboard for a hand-held information processing device that can switch to keyboard function automatically after completion of data synchronization.
The present invention is generally directed to an input apparatus of a hand-held information processing device for selectively connecting the hand-held information processing device to a computer. According to one aspect of the invention, the input apparatus includes a main connection port, a transmission port, a route selection unit and a user selection device. The main connection port is adapted to connect the hand-held information processing device and the transmission port is adapted to connect the computer. The route selection unit, coupled between the main connection port and the transmission port, is configured to selectively establish a first transmission route between the main connection port and the transmission port. The user selection device is configured to selectively output a first logic level and a second logic level. Moreover, the user selection device outputs the first logic level to cause the route selection unit to cut the first transmission route, and the user selection device outputs the second logic level to cause the route selection unit to make the first transmission route conductive.
According to another aspect of the invention, a portable keyboard is provided for use in a hand-held information processing device. The portable keyboard has a keyboard controller, a serial transmission port, a main connection port, a route selection unit, a sync button and a combinational logic circuit. The keyboard controller includes a keyboard transmit data pin and a keyboard control pin. The serial transmission port includes a serial transmit data pin and a data set ready pin. The main connection port has a serial receive data pin, a main control pin and a data terminal ready pin, and the main connection port is adapted to connect the portable keyboard to the hand-held information processing device. The route selection unit is responsive to a select signal. When the select signal is at a first logic level, the route selection unit is configured to electrically couple the keyboard transmit data pin to the serial receive data pin, to electrically couple the keyboard control pin to the main control pin and make the data terminal ready pin electrically floating. When the select signal is at a second logic level, the route selection unit is configured to electrically couple the serial transmit data pin to the serial receive data pin, to electrically couple the data set ready pin to the data terminal ready pin and make the main control pin electrically floating.
Furthermore, the sync button has a first output terminal electrically coupled to the main control pin and has a second output terminal. The sync button provides the first logic level and the second logic level at the first output terminal and the second output terminal, respectively. The combinational logic circuit is used to produce the select signal. One input terminal of the combinational logic circuit is electrically coupled to the data set ready pin, and the other input terminal of the combinational logic circuit electrically is coupled to the second output terminal of the sync button. Additionally, the combinational logic circuit sets the select signal to the second logic level except when the second output terminal of the sync button and the data set ready pin both are at the first logic level.